US5052832A - Print head and roller biasing mechanism for a hand held thermal printer - Google Patents

Abstract

A hand held printer for printing on a print paper when the printer is manually moved over the surface of the paper is provided, including a print mechanism supported within the housing to print inputted characters and drawings on the print paper upon manual manipulation of the housing. A thermal head is movably supported within the housing. A movement measurement unit indicates movement of the printer. A drive roller drives a ribbon take up roller and movement measurement unit. A clutch allows the drive roller to function only in a printing direction. A spring biases the drive roller towards an operating position, the drive roller moving to the print surface independently of the thermal head when the drive roller is biased by the spring.

Description

This is a division of application Ser. No. 198,536, filed on May 25, 1988.

BACKGROUND OF THE INVENTION

The present invention relates generally to a hand held printer which prints both characters and drawings on a print paper in response to manual movement of the printer over the surface of the print paper, and more particularly, to a hand held printer which incorporates an input unit, a display unit, a character storage unit and a printing device in a single housing.

In order to understand the background of the invention, reference is first made to FIG. 1 wherein a conventional hand held printer, generally indicated at 100, for printing on a print paper through manual movement over the paper, is depicted. Because of the manual operation of such hand held printers, the plurality of motors usually required to drive a normal carriage contained printer and the control circuits for controlling those motors are not needed thereby allowing for greater miniaturization and portability. However, to control the printing, the conventional hand held printer has to be connected to alarge host unit 75 through interface cables 74A and 74B.Printer 100 has a manually movable body 70 movable over aprint surface 160 which contains aposition detector 72 which is rotated by aroller 69 when body 70 is manually moved overprint surface 160. Anencoder 73 detects the motion ofposition detector 72 and produces signals which are detected byhost unit 75.Host unit 75 detects the pulse signals fromencoder 73 and a control unit withinhost unit 75 outputs a pattern of characters and drawings to a print head 71 in response to the pulse signals fromencoder 73 in order to print onsurface 160 as printer body 70 is moved thereover. In such an apparatus, the pattern of the characters and drawings to be printed by print head 71 are input using a separate input unit 76, aseparate display unit 77 and a separate storage unit inhost unit 75. Such a conventional printer is disclosed in U.S. Pat. No. 3,767,020, issued Oct. 23, 1973 to Rowe.

Conventional hand held printers are known in the art as illustrated by Japanese Laid Open Patent Nos. 60-109866, 62-244683 and 61-283574 and Japanese Laid Open Utility No. 61-16685. In these conventional hand held printers, a thermal ink ribbon is sandwiched between a fixed roller and the print surface. The ink ribbon is moved by the manual movement of the hand held printer over the print paper. Printing may also be accomplished by pressing the printer on the paper and manually moving the printer to perform the printing.

Additionally, many hand held lettering tape printing devices have also been proposed. These require a motor for driving the roller which draws out the ink ribbon and the lettering tape as well as motors for controlling the ink ribbon take up reel. Additionally, a control circuit for controlling the motor is required resulting in a large sized apparatus. Accordingly, printing is possible only on special lettering tapes.

These hand held printers have been less than satisfactory. It is impossible to use the conventional hand held printer without the associated input unit, display unit, storage unit and control unit of a host unit. Accordingly, even if the hand held printer is small and portable the apparatus itself is not portable due to the large sized associated control units. Additionally, the structure of the prior art hand held rollers results in unstable application of pressure by the thermal head and the roller on the ink ribbon during manual operation. Accordingly, only the pressure of the thermal head acts on the ribbon and the pressure applied on the ribbon by the printing surface of the roller is either very small or non-existent. When this occurs, the roller cannot rotate and it becomes impossible to feed and take up the thermal ink ribbon. The thermal ink ribbon runs out from the printer causing undesirable staining of the print surface making a usable print operation impossible. Furthermore, the print roller slips due to the interlocking of the thermal ink ribbon during operation. When the roller does slip, it falls out of sync with the signal sent by the encoder corresponding to the displacement of the hand held portion of the printer across the surface. Because the host unit no longer has accurate data as to the distance moved by the hand held printer, the characters or drawings are printed out of sync with the actual displacement of the printer resulting in misformed printed symbols.

The roller also acts as the ink ribbon take up roller for the used up thermal ink ribbon. The roller relies on the driving forces generated by the friction of the roller engaged with the print surface when the roller presses the ink ribbon onto the printing paper during operation. This requires that a large downward force be applied to the printer to obtain an adequate friction and driving force to take up the thermal ink ribbon. When such a force cannot be provided, the ribbon is not taken up by the roller, resulting in the thermal ink ribbon running out from the printer causing major defects in the printed symbol such as staining of the printed surface making operation of the printer impossible. On the other hand, when large forces are applied to the hand roller they tend to damage the hand held printer due to deterioration of parts due to the operation under high pressures, forces and stresses.

Additionally, the conventional hand held printers do not contain a ribbon guide member for guiding the travel direction of the thermal ink ribbon through the printer during printing. This results in displacement, loosening, jamming and the projecting of the ink ribbon from the thermal head during operation causing deterioration of print quality and deterioration in the maintainence of print consistency during operation. Such conventional hand held printers which do include a ribbon guide still result in handling problems of the travelling surface resulting in poor operation, detachment of the ribbon when the ribbon cassette is detached from the hand held printer and related problems. Additionally, due to the gap between the thermal head and the print surface or inconsistencies in the print surface, the thermal ink ribbon and thermal print head do not closely adhere to the printing surface causing misprinting of the symbols to create light and dark areas.

Accordingly, it is desired to provide an improved hand held printer which overcomes the shortcomings of the prior art and which achieves the objects and benefits associated with a completely portable, manually activated printer.

SUMMARY OF THE INVENTION

Generally speaking, in accordance with the present invention, a hand held printer which prints on a print paper by manual movement of the printer on the surface of the paper, is provided. A housing supports a thermal head. A thermal transfer ink ribbon is supported within the housing and is collected on a take up roller. A driving roller is engaged with the take up reel. The ink ribbon passes over the driving roller prior to being wound up on the take up reel. A printer movement detector detects the relative movement of the hand held printer over the print paper and provides a control signal to a control unit in the housing which controls the relative operation of the thermal head. A character input device and display device are both contained within the housing. The drive roller is displaced to come in contact with the printing surface.

The housing may also include roller guides formed as groove shaped members for supporting the drive roller so that it is slidable relative to the printed surface. A support member supports the drive roller within the housing and is rotatable relative to the printed surface. The drive roller may also be constructed with a concave portion for receiving the thermal ink transfer ribbon and allowing the thermal ink transfer ribbon to pass about the concave portion of the drive roller.

The printer may also include a thermal ribbon guide for positioning a thermal ribbon relative to the thermal print head. The ribbon is stored in a ribbon cassette which includes the thermal ribbon. When attaching or detaching the cassette from the housing, the ribbon guide engages a slide guide which is slidable relative to the printed surface and is opened and closed in a direction away from the thermal ribbon and the ribbon cassette. The ribbon is also guided by a roller which is rotatably mounted to trail the thermal head during operation of the hand held printer.

The hand held thermal head printer may also include a tape storage reel and a roller platen for pressing the tape surface against an ink ribbon and thermal print head. A detector for detecting the amount of tape travelling past the thermal head is also provided.

Accordingly, it is an object of this invention to provide an improved hand held printer which prints on a paper when the printer is manually moved on the surface of the paper.

Another object of this invention is to provide a hand held printer which is small enough to be conveniently used.

A further object of the present invention is to provide a hand held printer which incorporates the input and display of the information to be printed into a single hand held unit.

Yet another object of the invention is to insure good print quality in a hand held printer by avoiding major defects through the smooth feeding and taking up of the thermal ink ribbon.

Still another object of the present invention is to provide a cover which opens and closes about the ink ribbon through sliding upon the application of pressure to provide a simple guide for the thermal ink ribbon.

Yet another object of the present invention is to provide a hand held printer having a detachable ink ribbon cassette and which provides excellent print quality.

Still a further object of the present invention is to provide a small portable tape printer using a general purpose tape in a simple mechanism.

Still other objects and advantages of the invention will in part be obvious and will in part be apparent from the specification and drawings.

The invention accordingly comprises features of construction, combination of elements and arrangements of parts which will be exemplified in the constructions hereinafter set forth and the scope of the invention will be indicated in the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

For a fuller understanding of the invention, reference is accompanying drawings, in which:

FIG. 1 is a schematic view of a hand held printer coupled to a large host unit constructed in accordance with the prior art;

FIG. 2 is a partially exploded perspective view of a first embodiment of a hand held printer in accordance with the present invention;

FIG. 3 is a bottom plan view of the thermal head used in the printer in accordance with the invention;

FIG. 4 is a block diagram depicting one embodiment of the control system of the hand held printer in accordance with the invention;

FIG. 5 is a front elevational view of a character input tablet in accordance with the invention;

FIG. 5A is an exploded view of the character input tablet of FIG. 5;

FIG. 6 is a schematic diagram indicating the input of a character on the input tablet of FIG. 5 showing the associated X--Y coordinates of the letter A;

FIG. 7 is a schematic view of a liquid crystal display in accordance with the invention;

FIG. 8 is a schematic view of a character storage RAM in accordance with the invention;

FIG. 9 is a perspective view of one embodiment of the printing mechanism of the hand held printer in accordance with the invention;

FIG. 10 is an exploded view of the printing mechanism depcited in FIG. 9 before an ink ribbon cassette is inserted in accordance with the present invention;

FIG. 11 is a sectional view of the printer mechanism in accordance with the invention;

FIG. 12 is a sectional view of the winding reel for the ink thermal ribbon in accordance with the invention;

FIG. 13 is a sectional view of the thermal head when pressure is applied thereto in accordance with the invention;

FIG. 14 is a sectional view of the ribbon cassette in accordance with the invention;

FIG. 15 is a schematic view of the printer portion of the printing mechanism of the hand held printer prior to application of pressure on the print paper;

FIG. 16 is a schematic view of the printer portion of the print mechanism of the hand held printer during printing after pressure is applied in accordance with the invention;

FIG. 17 is a perspective view of the print head-drive roller assembly of the hand held printer in accordance with the invention;

FIG. 17A is a perspective view showing a one way clutch constructed in accordance with the invention;

FIG. 17B is a sectional view of the one way clutch of FIG. 17A;

FIG. 17C is a sectional view of the one way clutch constructed in accordance with the invention;

FIG. 18 is a partial view of the driving roller prior to manual operation of the print roller in accordance with the invention;

FIG. 19 is a partial view of the drive roller during manual operation of the hand held printer in accordance with the invention;

FIG. 20 is a schematic illustration of one embodiment of the printing mechanism of the hand held printer in accordance with the invention;

FIG. 21 is a schematic illustration of a second embodiment of the printing mechanism of the hand held printer in accordance with the invention;

FIG. 22 is a perspective view depicting an example operation of the hand held printer in accordance with the invention;

FIG. 23 is a bottom perspective view of a printing mechanism for the hand held printer in accordance with an embodiment of the invention;

FIG. 24 is an exploded view of the ribbon cover and slide plate assembly of the printing mechanism in accordance with the invention;

FIG. 25 is a perspective view of the ribbon cover and slide plate assembly of the printing mechanism in accordance with the invention;

FIG. 26 is a schematic view of the operation of the ribbon cover and drive roller assembly prior to manual operation of the hand held printer before pressure is applied in accordance with the invention;

FIG. 27 is a schematic view of the ribbon cover and drive roller assembly during printing of the hand held printer in accordance with the invention;

FIG. 28 is a cross sectional view of a thermal ribbon guide portion depicted in FIG. 27 in accordance with an embodiment of the invention;

FIG. 29 is an elevational view showing the clearance according to an embodiment of the invention;

FIG. 30 is a perspective view of the ribbon cover of FIG. shown after formation of the letter A according to an embodiment of the invention;

FIG. 31 is a perspective view of the printing mechanism of the hand held printer depicting the operation of the ribbon cover in accordance with an embodiment of the invention;

FIG. 32 is a perspective view showing the opening of the ribbon cover and the detachment of the ribbon cassette of the hand held printer in accordance with the invention;

FIG. 33 is a sectional view of the printing mechanism of the hand held printer in accordance with another embodiment of the invention, shown prior to printing;

FIG. 34 is a sectional view illustrating the printer portion of the embodiment depicted in FIG. 33 prior to the application of manual pressure;

FIG. 35 is a sectional view similar to FIG. 34 illustrating the printer portion of the hand held printer during printing after pressure has been applied;

FIG. 36 is a perspective view of the printer portion of the printing mechanism depicted in the embodiment of FIG. 33;

FIG. 37 is a schematic diagram illustrating the basic movement of the drive roller and print head in accordance with the embodiment of the invention depicted in FIG. 33;

FIG. 38 is a sectional view depicting the operation of the ribbon cover prior to printing before pressure is applied in accordance with the embodiment of the invention depicted in FIG. 33;

FIG. 39 is a sectional view depicting the operation of the ribbon cover in accordance with the embodiment of the invention depicted in FIG. 33 during printing after pressure is applied;

FIG. 40 is a sectional view of the ribbon guide depicted in FIG. 39 in accordance with the embodiment of the invention depicted in FIG. 33; and

FIG. 41 is a schematic view of another embodiment of the hand held printer in accordance with the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference is first made to FIGS. 2 and 3 wherein a hand held printer, generally indicated as 68, is depicted.Printer 68 includes a body orhousing 1 which supports therein aprinting mechanism 5 including athermal head 2 forming the printing apparatus of the hand heldprinter 68. A rotatable detecting plate 3 for detecting the amount of movement ofprinting mechanism 5 relative, to aprint surface 160 is provided. Aphoto detector 4 ofprinting mechanism 5 cooperates with detecting plate 3 for indicating the amount of movement ofprinter 68. Atablet 9 for inputting the characters to be printed and a dot matrixliquid crystal display 10 for displaying the characters to be printed are supported on the front side ofhousing 1. Acontrol unit 11, which includes a storage unit such as memory unit 55 and a character generator is 27 (FIG. 4) is supported withinhousing 1 behindprinting mechanism 5 and controls the operation ofprinter 68.Batteries 12 act as a power source for theprinter 68 and are retained in the top half ofhousing 1.Tablet 9 andliquid crystal display 10 are coupled to controlunit 11 through aflat cable 13.Photo detector 4 is coupled to controlunit 11 through acable 14, andthermal head 2 is coupled to controlunit 11 throughcable 15.

A thermal transfer tape orribbon 16 travels throughhousing 1 and is wound about take up reel 8. Adrive roller 6 engagesprint surface 160 to rotate in the direction of arrow B whenprinter 68 is operated and manually moved along theprint surface 160 in the direction of arrowA. Drive roller 6 engages atransmitting gear 7 which in turn engages take up reel 8 and detecting plate 3 causing each to rotate upon movement ofdrive roller 6.Printing mechanism 5 is constructed to perform printing by slidingbody 1 in the direction of arrow A onprint surface 160.

As shown in FIG. 3,thermal head 2 includes a plurality of heating elements 2-2 which are aligned at one end of the surface of a substrate 2-1 ofthermal head 2. A driver 2-3 for supplying current to heating elements 2-2 is aligned with heating elements 2-2.Thermal head 2 is supported inhousing 1 at an incline towardthermal transfer ribbon 16, enabling further miniaturization ofprinter 68, while attaining an effective use of available space withinhousing 1.

The side on whichtablet 9 anddisplay 10 are located onhousing 1 may be formed with a hingemechanism including hinge 500 and pin 501 or the like to allow opening and closing ofhousing 1 ofprinter 68.

Reference is now made to the block diagram of FIG. 4 to describe the operation ofprinter 68.Printer 68 includes aninput unit 51 for inputting the characters to be printed, adisplay unit 53 for displaying the printed characters, a memory or storage unit 55 for storing the input symbols and aprinting unit 57.Input unit 51 includestablet 9 and atablet control circuit 22.Display unit 53 includesliquid crystal display 10 and a liquidcrystal driving circuit 23. Memory unit 55 includes aRAM 24 and an associated backup power source 25.Printing unit 57 includesthermal head 2 and ahead driving circuit 21. Adetector 58 for detecting the amount of movement during manual operation ofprinter 68 includes detecting plate 3 andphoto detector 4.Photo detector 4 outputs a detecting signal corresponding to the amount of movement ofprinter 68 which is input to a central processing unit of a direct control unit (CPU) 20. Aprint character generator 27causes printing unit 57 to print characters. Similarly, adisplay character generator 28 causes display 10 to display characters. The control unit includesCPU 20 and aROM 26 for controlling each of the units. As aforenoted,batteries 12 act as the main power source.

Reference is now made to FIGS. 5 and 5A whereininput tablet 9 is depicted in detail.Tablet 9 is a small input unit and includes agum sheet 47 located at the surface oftablet 9 and an insulatingsheet 52 andsubstrate 53 disposed beneath thegum sheet 47 and separated therefrom by a slight gap. A plurality ofelectrodes 48 forming lines extending in the X direction separated at predetermined intervals are formed on the inner side ofgum sheet 47. A plurality ofelectrodes 49 forming lines extending in the Y direction, perpendicular to the lines formed in the X direction, at predetermined intervals are formed on the insulating sheet. Eachelectrode 48 will cross eachelectrode 49 in spaced relation at a right angle. Accordingly, if the surface ofgum sheet 47 is traced by a handwriting implement on its display side,electrodes 48 and 49 in the corresponding X and Y directions below the trace portion are sequentially contacted. Each contact produces a signal so that the cross point of eachelectrode 48 and 49 is detected and input totablet control circuit 22 through its respectiveconductive lines 45 and 46. As seen in FIG. 5A,gum sheet 47 is provided to cover thesurface tablet 9.Tablet 9 includes agum sheet 47,vinyl sheet 51, an insulatingsheet 52 and asubstrate 53. Insulatingsheet 52 acts as ground.Electrode 48 is printed on the rear surface ofvinyl sheet 51 andelectrode 49 is printed on a surface ofsubstrate 53. When pressure is applied togum sheet 47 by a pen or the like, which pressure is sensed so thatelectrodes 48 and 49 are grounded to the insulatingsheet 52 and the potential becomes 0.

Eachelectrode 48, extending in the X direction is connected to oneconductive line 45 and similarly, eachelectrode 49 extending in the Y direction is connected to oneconductive line 46. By pressing one point on thetablet 9, the respective terminals ofconductive lines 45 and 46 extending from the side oftablet 9 detect the press point as a respective X coordinate value and a respective Y coordinate value. Accordingly, a symbol may be considered as a group or set of coordinate points found on an X, Y plane.Tablet control circuit 22 detects these X, Y coordinate values and transmits this data toCPU 20 in response to atrigger signal 29 fromCPU 20.

Tablet 9 has on itssurface input portions 31 and 32 for inputting characters and inputting drawings.Cursor control keys 33, 34, 35 and 36 are provided for indentifying the characters. Editingkeys 41, 42, 43 and 44 edit the characters input oninput portions 31 and 32. Aprint key 37 initiates printing and apower switch 38 provides on-off operation of the device.Memory keys 39 and 40 are also provided. When a small letter is to be input,portion 32 oftablet 9 located at the lower right hand corner ofportion 31 for inputting larger letters is provided.

Letters are input throughtablet 9 by on-line handwriting of the letter in eitherinput portion 31 orinput portion 32. As shown in FIG. 6, a letter or character drawing input intoportion 31 oftablet 9 may be represented by a series of X, Y coordinates which follow the handwritten trace lines. For example, the letter A is written with three traced lines a, b and c. Line a may be represented as a series of points along the grid formed byelectrodes 49, 48 such as (2, 2) (3, 4) (4, 6) . . . (5,9). Similarly, the line b is represented as the coordinate points (5, 9) (6, 8) (7, 6) . . . (9,2). The third line c is represented as (3, 4) (4, 4) (5, 4) . . . (8,4). Accordingly, the handwritten information which is input is transformed into usable data forCPU 20.

After a first letter is written, execute key 44 is pushed. This causes thetransfer signal 29 to be sent fromCPU 20 totablet control circuit 22 causingtablet control circuit 22 to transfer the above values of each X coordinate and corresponding Y coordinate toCPU 20.CPU 20 performs pattern matching of the obtained values for each X coordinate and Y coordinate with standard traced data stored within aROM 26. The inputted trace data transmitted bytablet control circuit 22 is compared with known expected values stored withinROM 26 so that a letter code of the character having a high consistent ratio with a pattern of recognized value is output as the letter code.

The letter code output fromCPU 20 is stored in storage unit 55 (RAM 24).CPU 20 calls a font corresponding to the letter code stored inRAM 24 from thedisplay character generator 28 and then transmits a character of that selected font font to the liquidcrystal driving circuit 23 which causes the display of the font onliquid crystal display 10.

Drawings are input by directly writing the drawing on character drawinginput portion 31 oftablet 9. To distinguish the character to be drawn from other inputs, the termination of the inputting of the character is signaled toCPU 20 through the pressing of aspace key 43 upon the completion of the inputting of the character. The drawings are also coded as above and stored byCPU 20 as coordinate points inRAM 24.

Letters and characters may be input as strings forming sentences. Amending and revising the inputted sentences is conducted through editing keys 41-44. Editing keys 41-44 include aninsert key 41, a delete/cancel key 42, a space/non-select key 43 and a carriage return execute key 44. During editing,CPU 20 recalls sentences stored in storage unit 55 (RAM 24) to perform the identifying, deleting, inserting and amending of the character in accordance with instructions from editing keys 41-44. During this time, the editing operation is displayed onliquid crystal display 10 through liquidcrystal driving circuit 23. As shown in greater detail in FIG. 7, acursor 50 appears onliquid crystal display 10 and is operated through cursor keys 33-36. A character exhibited onliquid crystal display 10 may be deleted through the use of delete key 42. To amend a sentence or character,cursor 50 is moved to the position or character to be amended, the character at that position is deleted through the use of delete key 42 and a character may be inserted at that position by utilizinginsert key 41. Through the use ofcursor 50, delete key 42 and insert key 41, amendment or revision of characters and sentences is performed.

Liquid display crystal 10 is a dot matrix liquid crystal display. As shown in FIG. 7, liquidcrystal driving circuit 23 includes afirst driving circuit 23a to driveliquid crystal display 10 in the column direction and a driving circuit 23b to driveliquid crystal display 10 in the row direction.Liquid crystal display 10 is of the dot matrix type which controls the on or off signal of each dot, enabling the display of relatively simple patterns such as characters, Chinese characters, drawings and the like. Liquidcrystal driving circuit 23 receives the dot pattern of the input characters and drawings fromCPU 20 to cause the displaying of the input characters and drawings at the associated dot positions as instructed byCPU 20.Cursor 50 is displayed onliquid crystal display 10 and as described above acts as a pointer during inserting and deleting of characters. The characters generated bydisplay character generator 28 are transmitted byCPU 20 to displayunit 53 and are displayed at the position ofcursor 50 onliquid crystal display 10.

Reference is now made to FIG. 8 wherein memory unit 55 is depicted.RAM 24 is divided into anediting region 60, a storingregion 61 and aprinting region 62. The letter codes of the sentence which is currently being edited are stored inediting region 60. Amemory cursor 63 acts as a pointer for indicating the position within editingregion 60 being edited. Theposition 66 being indicated bycursor 63 is identical to the position being indicated bycursor 50 ondisplay 10. By pressing save key 39 oftablet 9, the sentence which is currently being edited is stored in storingregion 61. Each sentence of characters is stored in its own portion of storingregion 61. Asecond memory pointer 64 indicates which sentence within storingregion 61 is presently being acted upon. Pushing memory load key 40 causes the sentence indicated bypointer 64 within storingregion 61 to be loaded intoediting region 60 and simultaneously be displayed onliquid crystal display 10.Pointer 64 is incremented after each loading. During the printing of the edited sentence,print region 62 signalsprint character generator 27 to print the letter codes corresponding to the code in theediting region 60 directly to printregion 62 thereby forming the letter font to be transmitted tothermal head 2.RAM 24 maintains the information stored therein through a backup power source 25 or battery even whenswitch 38 is turned off.

Printing is begun by pressingprint starting key 37 located ontablet 9.CPU 20 calls the letter code of the sentences to be printed from the corresponding codes ofprint character generator 27 and signals printcharacter generator 27 to transmit this information to printregion 62 withinRAM 24.Printer 68 is now prepared for printing and will begin printing upon manual operation through movement against aprint surface 160.Printer 68 is lifted and then pressed against aprint surface 160, such as print paper, and slid in the direction of arrow A (FIG. 2). This causesroller 6 to rotate causingtransmitting gear 7 to rotate causing the rotation of the detection plate 3 causingphoto detector 4 to generate pulse signals.CPU 20 detects these pulse signals and senses the sliding ofprinter 68. In response to the pulse signals,CPU 20 causes theprint character generator 27 to send print codes tothermal head 2 thereby effecting printing on theprint surface 160. Because the input speed ofdetector 4 is in response to the actual slide speed ofprinter 68 onprint surface 160, it becomes possible to print the characters and drawings uniformly since the output of theprinter 68 is synchronous with the speed of movement.

Ribbon take up reel 8 rotates simultaneously with transmittinggear 7 causingribbon 16 to be rolled up at the same rate as the print speed.

Battery 12 is used as a power source supplying power to head drivingcircuit 21,tablet driving circuit 22,CPU 20 andROM 26,print character generator 27 anddisplay character generator 28.RAM 24 has an independent back up power source 25 such as a battery.

By providing aninput 51, adisplay 53 and aprinting mechanism 5 as well as an apparatus for controlling these mechanisms all within a single hand-heldhousing 1, the printing operation from inputting through printing of characters and drawings by a hand held printer is now possible in a single operation utilizing a single portable device.Tablet 9 is used as an input by way of example only. Inputting may be possible utilizing a small keyboard for inputting all of the characters as well, or other input systems may be utilized.

Reference is now made to FIGS. 9 through 14 and 17 through 23, wherein theprinting mechanism 5 ofprinter 68 is depicted in detail. Aframe 120 supports athermal head 101 which is mounted about ashaft 111a extending fromframe 120. Adrive roller 102 is rotatably mounted withinframe 120 about ashaft 102b so as to trailthermal head 101 ifframe 120 were moved in the direction of arrowA. Drive roller 102 is formed with aconcave section 102c. Athermal ink ribbon 103 which passes acrossthermal head 101 and acrossdrive roller 102 travels throughprinter 68.Concave portion 102c acts as a guide forthermal ribbon 103. Driveroller 102 includes a one-way clutch which allows for rotation ofdrive roller 102 only in the direction of arrow B corresponding to movement ofprinter 68 in a print direction of arrow A (FIG. 11). Atransmitting gear 104 is rotatably supported withinframe 120. Adriving gear 102a is integrally formed ondrive roller 102 and transmits a driving force to transmittinggear 104. Driveroller 102 is formed with afirst gum roller 102d and asecond gum roller 102e formed at either side ofdrive roller 102 to come in contact withprinting surface 160 thereby causing the rotation of the entire printing mechanisms without slippage.Concave section 102c is made of a low friction material for reducing the friction force between the back coating ofthermal ribbon 103 so thatthermal ribbon 103 easily passes aboutdrive roller 102 without any excess load. As seen in FIGS. 17a, 17B and 17C a rotating bearing 102g is provided betweenaxis 102b andgum roller 102e. Whengum roller 102e is rotated toward arrow M, arrow C in FIG. 17A, bearing 102g is rotated withinrecess 102f in a free moving manner. However,gum roller 102e is rotated in the direction of arrow M', bearing 102g is quickly brought in contact withgum roller 102e andaxis 102b and remains in a locked condition known as a one way clutch generally indicated as 102i.

A detectingplate 106 formed with a plurality of openings 106b about its circumference is rotatably mounted onframe 120. A detectinggear portion 106a of detectingplate 106 engages transmittinggear 104 thereby, rotating withdrive roller 102 and transmittinggear 104. Aphoto interrupter 105 is triggered by openings 106b when detectingplate 106 is rotated.Photo interrupter 105 produces pulse signals in response to the movement ofdrive roller 102. Apress spring 113 is located on the face of detectingplate 106 providing a friction load to detectingplate 106 preventing the production of surplus pulses byphoto interrupter 105 due to over rotation of detectingplate 106 due to the inertia of rotation.

A ribbon take upcore 108 is rotatably mounted inframe 120. A transmittingplate 107 rotatably mounted inframe 120 has agear portion 107a which engages transmittinggear 104. Ribbon take upcore 108 includes a ribbon take upshaft 108a and a friction plate 108b composed of a high friction material such as felt or the like. Ribbon take upcore 108 is engaged with ribbon take upshaft 108a through the friction inherent from pressing against each other. Aspring 108c mounted about ribbon take upshaft 108a behind transmittingplate 107biases transmitting plate 107 against ribbon take upcore 108. Transmittingplate 107 engages ribbon take upcore 108 through the friction between ribbon take upshaft 108a and the friction plate 108b. Transmittingplate 107 rotates faster than ribbon take upcore 108, therefore transmittingplate 107 is constructed to prevent the loosening of thethermal ribbon 103 as it is wound about take upcore 108. Ribbon take upcore 108 is constructed to engage with aribbon cassette core 142a of aribbon cassette 140.

Asupport roller 109 is rotatably mounted about ashaft 109a onframe 120 on the opposite side ofthermal head 101 fromdrive roller 102.Support roller 109 is formed with aconcave section 109b to allow passage ofthermal ribbon 103 aboutsupport roller 109 and guidethermal ribbon 103 towardsthermal print head 101.Concave portion 109b provides clearance between theprint surface 160 andsupport roller 109 to allowthermal ink ribbon 103 to pass beneath hand heldprinter 68. Agum roller 109c is provided on the circumference ofsupport roller 109 to contact printedsurface 160 and to provide clearance betweenconcave region 109b andprint surface 160.

Aroller press spring 110 engages aprojection 120a extending fromframe 120, thereby biasingshaft 102b ofdrive roller 102 in the direction of arrow N (FIG. 11), towardsprint surface 160.roller shaft 102b is guided by aguide groove 120d offrame 120 to allow slidable movement ofshaft 102b along a predetermined distance in the direction of arrows N and N'.Thermal head 101 includes adissipation plate 101c for improving the thermal responsiveness and print quality ofthermal head 101 by providing a heat sink for allowing the heat to escape fromthermal head 101 during operation.Dissipation plate 101c is held tothermal head 101 by ahead holder 101b.Head holder 101b is engaged by ahead pressing plate 101e through ahead holder shaft 101d.Thermal head 101 andheat dissipation plate 101c are rotatable in the direction of arrow E (FIG. 13) abouthead holder shaft 101d. Ahead pressing spring 111 mounted aboutpivot 111a presses head pressingplate 101e toward printedsurface 160Head pressing plate 101e is rotatable in the direction of arrow D about thehead pressing shaft 111a.Head pressing spring 111 is anchored at aprojection 120b offrame 120.Thermal head 101 is controlled so that the displacement due to rotation in the direction of arrow E and the rotation in the direction of arrow D" is stopped at a predetermined position by astopper 101f mounted onhead holder 101b andstopper portion 120c provided onframe 120.

A ribbon cover, generally indicated as 130, acts as a guide forthermal ribbon 103 as it passes throughentrance 140c orexit 140d ofribbon cassette 140.Ribbon cover 130 is supported on aslide plate 135 by astopper pin 132. As will be discussed in greater detail below,slide plate 135 is slidably guided in the direction of arrow F (FIG. 33) to allowprinter 68 to followprint surface 160.Slide plate 135 is slidably mounted onframe 120 throughguide portions 120e, 120f and 120g offrame 120. Aguide pin 136 is attached throughframe 120 and slidecontrol hole 135b provided onslide plate 135 to affixcover 130 toframe 120. Additionally,slide plate 135 is pressed in the direction ofprint surface 160 by a pair ofsprings 121 so thatslide plate 135 is maintained at a predetermined position byguide pin 136 and slidecontrol hole 135b.

Ribbon cassette 140 is detachably attached to frame 120 by two snapfit portions 140a ofribbon cassette 140.Ribbon cassette 140 is attachable to frame 120 by one touch in the direction of arrow I (FIG. 10) towardspositioning portion 120j and 120k provided onframe 120.

Aribbon cassette core 142b engages with ribbon take upcore 108 while aribbon cassette core 142a engages a core 112 rotatably mounted onframe 120. A take up force is transmitted toribbon cassette core 142b from ribbon take upcore 108 to take up the usedthermal ribbon 103b, winding the usedthermal ribbon 103b aboutribbon cassette core 142b. The unused portion ofthermal ribbon 103a is wound throughribbon cassette 140 and is stretched as it passes through acassette arm 140e to preventthermal ribbon 103 from loosening. The take up force transmitted toribbon cassette core 142b provides a control force like a brake providing tension for preventingthermal ribbon 103 from becoming loose at the side of the ribbon feeder.

Acable 180 of the FPC type or the like couplesthermal head 101 andphoto interrupter 105 to print driving controllingcircuit 11.

A separatingroller 131 is rotatably and detachably mounted onribbon cover 130 betweenthermal head 101 and driveroller 102.Separation roller 131 is positioned betweenthermal ribbon 103 andprint surface 160 for separatingthermal ribbon 103 fromprint surface 160 just after printing has been performed bythermal head 101.

Reference is now made to FIGS. 24 through 27 whereinribbon cover 130 andslide plate 135 are depicted in detail.Ribbon cover 130 is formed with twoopenings 130c, one being located at each side ofribbon cover 130.Openings 130c form cassette positioning guide portions which engage withthermal ribbon exit 140c andthermal ribbon entrance 140d ofcassette 140.Inner walls 130e, 130f and 130g are formed at the edge of eachopening 130c and form cassette positioning guide portions onribbon cover 130 to control movement ofthermal ribbon 103 across its width. The resulting inner walls act to control the position ofthermal ribbon 103 on its route betweeninner walls 130e and 130g.

Ribbon cover 130 is coupled to slidecover 135 by astopper pin 132 inserted into astopper hole 130a ofribbon cover 130 and arotary hole 135a ofslide plate 135 as shown in FIG. 24. Becausestopper pin 132 is rotatable when positioned inrotary hole 135a,ribbon cover 130 can open and close relative to slideplate 135. Therefore, whenribbon cover 130 is attached to frame 120,ribbon cover 130 is controlled byframe 120 to only open to a predetermined angle. When closingribbon cover 130 relative to slideplate 135, closing is realized by engaging the snapfit portion 130d ofribbon cover 130 withpositioning groove 135d ofslide plate 135. Snapfit portion 130d securesribbon cover 130 preventingribbon cover 130 from freely opening and closing.

In the structure formed byribbon cover 130 andslide plate 135, anarm portion 135e ofslide plate 135 is inserted in the region of a slide guide formed fromguide portions 120e, 120f and 120g offrame 120. Additionally,guide pin 136 is inserted through aguide pin hole 120h (FIG. 23) offrame 120 and throughslide control hole 135b ofslide plate 135, thereby slidably guiding the slide unit in the direction of arrow F (FIG. 33). Aspring 121 is affixed in astopper end 135c ofarm portion 135e and stopper end 120i offrame 120 thereby pressing the slide unit in the direction ofprint surface 160, i.e. the direction of arrow F'ribbon cover 130 shown in phantom as 130' (FIG. 31), while the slide unit is controlled to maintain a predetermined position byslide control hole 135b. Accordingly,printer 68 is constructed so as to guide the projection ofthermal head 101 and the traveling ofthermal ribbon 103 as well as pressingink ribbon cover 130 againstprint surface 160.

Reference is now made additionally to FIG. 22 to explain operation ofprinter 68. Acase 150, forming the housing forprinter 68, is pressed towardsprint surface 160 in the direction of arrow P by thehand 170 of the user.Case 150 is then moved in the direction of arrow A rotatingdriving roller 102 due to the friction betweenprint surface 160 and driveroller 102. Synchronous signals for printing are generated byphoto interrupter 105 causingthermal head 101 to printcharacters 162 onprint surface 160 in accordance with data stored inRAM 24.

Reference is now made to FIGS. 15 through 20. When pressure is not applied tocase 150 in the direction ofprint surface 160 by thehand 170 of a user, the relative positioning ofdrive roller 102,support roller 109,thermal ribbon 103 andthermal head 101 is as shown in FIG. 15. In this position,thermal head 101 is positioned so thatdrive roller 102 andsupport roller 109 contact printedsurface 160 andthermal head 101 is held at a predetermined distance h fromprint surface 160 bystopper 101f which controls the movement ofthermal head 101.

When downward pressure is applied tocase 150 byhand 170, the relative position ofdrive roller 120,support roller 109 andthermal head 101 is as depicted in FIG. 16. The pressure applied byhand 170 readily displacesdrive roller 102 in the direction of arrow L' relative to frame 120. Driveroller 102 is smoothly displaced in the direction opposed to printsurface 160. Afterdrive roller 102 is securely pressed to printsurface 160,thermal head 101 further moves in the direction of arrow D' causinghead spring 111 to pressthermal head 101 in the direction of arrow D", thereby causing distance h to approach zero. Due to the pressure applied byhand 170, the condition ofprinter 68 is changed from that depicted in FIG. 15 to that depicted in FIG. 16.Thermal head 101 moves to a printing condition afterdrive roller 102 is securely pressed to printsurface 160.Thermal head 101 cannot be pressed to print surface 76 entirely prior to pressingdrive roller 102 to printsurface 160.

Additionally, all that is required is that the pressure due to the driving force obtained from the friction force betweendrive roller 102 andprint surface 160 is minimally larger than the driving force obtained by thedrive roller 102 at the position when thedrive roller 102 starts to move by pressingdrive roller 102 towardsprint surface 160.

Accordingly, in the conventional hand held printer, since the value of h is equal to or less than zero, the drive roller cannot rotate as described above. As a result, printing starts before there has been a sufficient take up of the thermal ribbon. Therefore, the thermal ribbon begins to run out from the printer causing staining of printing and deterioration of print quality as well as operation failure. The present invention makes it possible to overcome these problems.

As can be seen in FIG. 17, due to the cylindrical shape ofdrive roller 102,thermal ribbon 103 may pass overdrive roller 102. The portion ofdrive roller 102 about whichthermal ribbon 103 passes isconcave portion 102c. Due toroller gum 102d, a guide is formed atconcave portion 102c for guiding a portion ofthermal ribbon 103 aboutdrive roller 102. Additionally, this provides clearance betweendrive roller 102 andprint surface 160 allowing easy passage ofthermal ribbon 103 belowprinter 68 during printing. If the portion ofdrive roller 102 over whichthermal ribbon 103 passes were cylindrical but did not have a concave shape, the ink ofthermal ribbon 103 would adhere to printsurface 160 causing staining during printing. In particular, becauseprinter 68 is continuously printing and the surrounding portion of the print spot where inkthermal ribbon 103 comes in contact withprint surface 160 due to pressure applied bythermal head 101 keeps changing, ifthermal head 101 is pressed to printsurface 160 bydrive roller 102, this changing portion of ink is transmitted to printsurface 160 forming a ghost character or causing a stain in the printing. On the other hand, when cylindrical shape ofdrive roller 102 does not come in contact with the passing portion ofthermal ribbon 103, the cylindrical shape of the passing portion can be used.

As seen in FIGS. 18 and 19,roller shaft 102b slides withinguide groove 120d offrame 120 in accordance with the movement ofdrive roller 102. The direction arrows L and L' correspond to the arrows in FIGS. 15 and 16.

Reference is now made to FIG. 20. Arrows L and L' correspond to arrows L and L' of FIGS. 15, and 16. The basic operation of the hand heldprinter 68 is dependent on whetherthermal head 101 moves towardprint surface 160 across a connecting line betweendrive roller 102 andsupport roller 109. The position ofthermal head 101 is the reference position for operation of the hand heldprinter 68. When no pressure is applied to theprinter 68,thermal head 101 is always located on the opposite side of the connecting line betweendrive roller 102 andsupport roller 109 atprinting surface 160. However, when pressure is applied to theprinter 68,drive roller 102 moves in the direction of arrow L' corresponding to the position shown asdrive roller 102' due to the relative movement ofprint surface 160 to position 160' causingthermal head 101 to cross the connecting line betweendrive roller 102 and driveroller 109 to the position of thermal head 101'. Accordingly, the position ofdrive roller 102' must always first be pressed towards theprint surface 160 making it possible for the movement of thermal head 101' to print surface 160' to be obtained by merely exerting enough pressure to movedrive roller 102 to driveroller position 102'. In the present embodiment, it is movement ofdrive roller 102 which causes movement ofthermal head 101 towardssurface 160. However, as seen in FIG. 21, operation of the hand heldprinter 68 may still be obtained from a structure having a fixeddrive roller 102.Support roller 109contacts print surface 160 and due the pressure applied to the printer is moved to the position corresponding to support roller 109' by the relative movement ofprint 160 to a position represented as print surface 160'. This results in the same condition provided ondrive roller 102 in FIG. 20, however, it is now made possible by the movement of 109.

Reference is now made FIGS. 26 through 32 wherein operation ofribbon cover 130 aribbon cassette 140 will be described.Spring 121 provides a F' which acts onribbon cover 130, causingribbon cover 130 to s at predetermined positions as shown in FIG. 31. When downward P is applied toprinter 68, a force F" acts onribbon cover 13 shifting the connecting line betweendrive roller 102 androller 109 as described above, causing the connecting line to coincide withprint surface 160.

As seen in FIG. 26, prior to the application of pressure,thermal ribbon 103 is barely engaged by the positioning control guides ofribbon cover 130 so that 103 is in an almost free floating condition withinribbon 130. When pressure is applied to hand heldprinter 68, as seen FIG. 27,thermal ribbon 103 becomes stretched to enable printing. Furthermore, ribboncassette exit opening 140c and ribboncassette entrance opening 140d engage with the positioning control guide portions ofribbon cassette 140 to prevent displacement, loosening, jamming and such betweenthermal ribbon 103 andthermal head 101. By pressingprinter 68 againstprint surface 160,print surface 160 provides a pressure F" againstribbon cover 130, thereby eliminating the gap between theprint surface 160 and the support forprint surface 160, thereby smoothing out any irregularities inprint surface 160. For example,print surface 160 may be paper having wrinkles therein. Accordingly,thermal head 101 andthermal ribbon 103 can adhere closely to printsurface 160 improving print quality.

As seen in FIG. 28, ribbon positioningcontrol guide portions 130e, 130f and 130g are formed onribbon cover 130.Control guide portions 130e, 130f and 130g are formed with a concave portion which acts to guidethermal ribbon 103 through the inner regions of the concave portion.

Reference is now made specifically to FIGS. 29, 30 and 32 with which operation ofribbon cover 130 will be described.Concave portions 130h and 130i are provided on the surface ofribbon cover 130 at the contact region ofribbon cover 130 againstprint surface 160 in the region whereprint character 162 is formed.Concave portions 130h and 130i do not contact each other, preventing separation of the ink fromprint character 162 which is caused by direct contact withprint character 162 which further increases print quality.

As described above,ribbon cover 130 is constructed for easy opening and closing so that whenribbon cassette 140 is being detached,ribbon cover 130 is opened in the direction of arrow G allowing the detachment ofribbon cassette 140 in the direction of arrow H (FIG. 32). When attachingribbon cassette 140,ribbon cover 130 is opened in the direction of arrow G to attachribbon cassette 140 in the direction of arrow H'.Ribbon cover 130 is then again closed in the direction of arrow G'. Accordingly, becauseribbon cover 130 may easily be opened and closed,ribbon cassette 140 is easily detachable.

After printing has occurred, a predetermined cooling period forthermal ribbon 103 occurs. This period occurs whenthermal ribbon 103 is separated fromprint surface 160. Because separatingroller 102 is separated a predetermined distance behindthermal head 101 in the path ofthermal ribbon 103, the separation of ink fromthermal ribbon 103 is achieved after the transferring of ink to printsurface 160 so that the resulting transferred ink may entirely harden. This provides for a good separation of ink fromthermal ribbon 103 and prevents reverse transfer of ink tothermal ribbon 103 Additionally, sinceroller 131 is rotatably attached toribbon cover 130, the unused ink which remains after printing ofthermal ribbon 103 and the remains of non-melted ink, does not remain on separatingroller 131. Whenprinter 68 is held during printing,thermal ribbon 103 is automatically separated fromprint surface 160 due to the friction force resulting during the take up ofthermal ribbon 103 and by the braking force ofsupport roller 109 located on the side supplyingthermal ribbon 103 tothermal head 101, thereby preventing any looseness inthermal ribbon 103 and any leakage of ink.

Reference is now made to FIGS. 33 through 40 which depict another embodiment of the invention. In this embodiment,support roller 109 has been replaced by aguide roller 114. Like parts are indicated with like reference numerals from the description above for the remaining parts. In this embodiment, pressure is applied toprint surface 160 in a perpendicular direction by hand 170 (FIG. 22), thereby providing a print condition withoutsupport roller 109 to provide the same printing effect as the above embodiment.

In the above embodiments, prior to manual operation ofprinter 68, when no pressure is applied toprinter 68, thermal head 101' and adrive roller 102' are positioned to be away fromprint surface 160 in the direction of arrow L'. Accordingly, driveroller 102 is always pressed to printsurface 160 beforethermal head 101 when pressure is applied in the direction ofprint surface 160 to perform manual operation ofprinter 68. Driveroller 102 can receive the rotary driving force during sliding ofdrive roller 102 away fromprint surface 160 due to the pressure applied to driveroller 102 byspring 110 to obtain the driving force required to drivedrive roller 102 due to the friction force resulting from interaction withprint surface 160. If further pressure is applied toprinter 68,drive roller 102 separates from printedsurface 160 in the reverse direction ofprint surface 160 once it reaches the bottom ofgroove 120d. Whenthermal head 101 is pressed to printsurface 160 throughthermal ribbon 103, the minimum pressure required for printing is obtained byhead pressing spring 111. Accordingly, the conditions necessary for printing are all provided. However, this results in unstable manual operation.

To perfect operation, if pressure is further applied toprinter 68 causingprint roller 102b to contact the top ofgroove 120d, the driving force ofdrive roller 102 and print pressure ofthermal head 101 increase to realize further stabilization during the print process. In the present embodiment, again it is always assured thatdrive roller 102 will be pressed againstprint surface 160 prior tothermal head 101, assuring the generation of a normal and secured detection signal, and normal feeding and taking up ofthermal ribbon 103. Additionally, ifdrive roller 102 is pressed to contact the upper end ofgroove 120d located away fromprint surface 160, the print pressure ofthermal head 101 can be secured, thereby enabling normal and secure printing.

Furthermore, in the first embodiment, whensupport roller 109 is added in addition todrive roller 102, the pressure applied toprinter 68 is received at two points. Accordingly, manual operation becomes more stable. And, as in the embodiment of FIG. 33, by substitutingshaft 114 forsupport roller 109, it is possible to rotatesupport shaft 114 aboutdrive roller 102, so thatdrive roller 102 can move more smoothly. Accordingly, although operation of another embodiment has been described in context of the first embodiment in which driveroller 102 is moved, it is possible to obtain the same printing effect from a structure in which supportshaft 114 is made to be moved as mentioned above.

Whendrive roller 102 has a cylindrical shape located on the portion ofdrive roller 102 wherethermal ribbon 103 passes aboutdrive roller 102,drive roller 102 andsupport roller 109 are formed with a concave shape so that passingthermal ribbon 103 may easily fit therein. Thereby, driveroller 102 can receive stable driving forces without any influence which may be caused by slippage ofthermal ribbon 103.Support roller 109 also receives stable support as a function of the lack of slippage ofthermal ribbon 103. Furthermore, it is possible to prevent staining and other imperfections of printing caused by adhesion of the ink ofthermal ribbon 103 to printsurface 160 due to pressure applied in a case where adrive roller 102 andsupport roller 109 are cylindrically shaped without the concave portion.

By providing for ribbon guides for controlling the travel of the thermal ribbon within the ribbon cassette and providing them on a slidable ribbon cover to remove any gaps between the printer and the print surface, loosening and jamming and such between the thermal ribbon and thermal head is prevented. Additionally, by opening and closing the cover which forms one portion of the ribbon guide means, the operation of detaching of the ribbon cassette is facilitated. Furthermore, by providing a separating roller which trails the thermal head during operation by a predetermined distance allows for the compulsory separating of the thermal ribbon from the print surface. By making the separating roller rotatable, unstable and left over ink is not transferred to the roller. Additionally, when the printer is stopped during operation, the separating roller prevents loosening of the ribbon and leakage of the ink due to its function of separating the thermal ribbon from the printed surface.

Furthermore, by providing a non-contact portion having a concave shape on the ribbon cover located at the portion of the ribbon cover where the characters are printed on the print surface, the separation after printing of ink which forms the printing character by being transferred from the thermal ribbon is prevented providing desirable print quality. Further, by providing a slidable ribbon cover which is acted upon by a pressure when engaging the print surface, the gap between the thermal head and print paper is removed smoothing out any irregularities in the paper with pressure providing close adhesion of the thermal head and the thermal ribbon to the print surface again improving print quality.

Reference is now made to FIG. 41 wherein another embodiment of the invention in which a printer using drawn out tape is provided. A body orhousing 81 supports a thermal print head 82. A head pressing spring 83 is mounted onbody 81 to provide a downward force on thermal head 82. Acable 84 connects thermal head 82 to a CPU 20 (FIG. 4). An adhesive tape 86 ("mending tape") is wound aroundtape holder 94. Athermal ribbon 85 is stored on asupply reel 91 and travels along a path past thermal head 82 to a take upreel 90. A roller type platen 87 pressesink ribbon 85 and mendingtape 86 against thermal head 82. A drive roller group, generally indicated as 88, consists of an upper roller 88a above mendingtape 86 and a lower roller 88b below mendingtape 86. Driveroller 88,sandwiches mending tape 86 from both above and below mendingtape 86 as shown in phantom and rotates as mendingtape 86 passes between rollers 88a, 88b whentape 86 is pulled in a direction of arrowK. Ink ribbon 85 also passes between rollers 88a and 88b prior to be wound on take upreel 90. Aspring 88c biases roller 88a against roller 88b.

A roller group generally indicated as 89separates mending tape 86 fromtape holder 94.Roller group 89 includes aside roller 89a above mendingtape 86, a roller 89b below mendingtape 86 and a spring 89c for biasingroller 89a against roller 89b. A detecting apparatus generally indicated as 92 detects the amount oftape 86 drawn out frombody 81. Detectingapparatus 92 includes aphoto detector 92a, a detectingplate 92b and a cable 92c for transmitting the output ofphoto detector apparatus 92 toCPU 20. Atiming belt 93 couples roller 88a to detectingplate 92b and take upreel 90 thereby transmitting the rotation of roller 88a to ribbon take upreel 90 and detectingplate 92b.

When mendingtape 86 is manually drawn out in the direction of arrow K, roller 88a rotates, rotating ribbon take upreel 90 and detectingplate 92bdue timing belt 93.Ribbon 85 is rolled up through the rotation of ribbon take upreel 90.Photo detector 92a generates pulse signals based upon the rotation of detectingplate 92b. WhenCPU 20 senses the generated signal, the pattern of characters and drawings are then output to thermal head 82 to cause printing.

Even when the draw out speed oftape 86 is varied to some degree, the generated pulse signals fromphoto detector 92a will also vary with the same degree thereby insuring uniform printing of characters and drawings.

A press spring 83 presses thermal head 82 towardsink ribbon 85 and mendingtape 86 against platen 87. Roller 89b acts to separate mendingtape 86 from mendingtape holder 94 when a drawing force is applied to mendingtape 86. Rollers 88a and 88b which rotate with the drawing out oftape 86, are pressed byspring 88c to preventribbon 85 and mendingtape 86 from sliding. The printer of FIG. 41 may accommodate different thicknesses of mendingtape 86 because of the spring mechansim which may vary the distances applied byroller groups 88 and 89.Roller group 88 includes a one-way clutch which prevents rotation of theroller group 88 in a reverse direction.

The present emobiment utilizes mending tape, however the printer is equally applicable to paper tapes and other tapes. Additionally, a transmission gear may be substituted for the timing belt.

By providing an extremely small hand held printer which includes the print mechanism, input and output of a single unit and which is manually operated, improved hand held printer which is applicable for wider usage than prior word processors and manual printers is obtained.

Furthermore, in accordance with the above embodiments of the invention, it is possible to obtain consistent and accurate print signals, feed ribbon and take up ribbon operations with an extremely simple mechanism. Additionally, misprinting due to deviations of the thermal ribbon, loosening, projecting, jamming and stepping out of the thermal ink ribbon from the thermal head are avoided providing an easily detachable ribbon cassette. Additionally, by reducing the pressure necessary to be applied to the body of the printer, staining of the characters and drawings just after printing is avoided. Further, by providing a slidable cover, the gap between the print surface and thermal head is removed preventing misprinting on crumpled paper surfaces. Accordingly, the present invention improves print quality operatability of the hand held thermal transfer printer thereby entirely removing faults of the prior art.

Additionally, by removing the driving motor and control circuit it is possible to even further miniaturize portable lettering printers utilizing a simple mechanism.

Additionally, in a hand held tape printing printer, by providing springs in the rollers, it becomes possible to use a variety of mending tapes.

It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efficiently obtained and since certain changes may be made in the above constructions without departing from the spirit and the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claims are intended to cover all the generic and specific features of the invention herein described and all statements of the scope of the invention which is a matter of language might be said to fall therebetween.

Claims (13)

What is claimed is:

1. A printing mechanism for a hand held printer which prints characters and drawings on a print paper by manual movement of said printer over the surface of said print paper, said printer being movable in a print direction and a nonprint direction over said print paper surface by manually pressing the printing mechanism to the print paper, the printing mechanism comprising a thermal print head movably supported in the printer, a thermal transfer ribbon supported in the printer, thermal head biasing means for biasing the thermal print head through the thermal transfer ribbon to the print paper, ribbon take up means for winding the ribbon, movement measurement means for generating a signal corresponding to movement of the printer over the print paper, drive roller means for driving the ribbon take up means and movement measurement means, clutch means engaging the drive roller means and only rotatable in the print direction, drive roller biasing means for biasing the drive roller means in a predetermined direction, and displacement means acting independently of the thermal head biasing means for moving the drive roller means independently of the thermal print head to the print surface when the drive roller means is biased by the drive roller biasing means.

2. The printing mechanism for a hand held printer of claim 1, wherein the displacement means includes guide means for guiding and engaging the drive roller means when the drive roller means is movable relative to the print surface.

3. The printing mechanism for a hand held printer of claim 2, wherein the hand held printer further comprises a frame having a groove therein, and the guide means includes the groove for supporting the drive roller means and said drive roller means is slidable relative to a print surface.

4. The printing mechanism for a hand held printer of claim 1, wherein the displacement means comprises a support member for supporting the thermal ribbon, the support member being rotatable relative to the print surface.

5. The printing mechanism for a hand held printer of claim 1, wherein a portion of the thermal ribbon passes about the drive roller means, the drive roller means being formed into a shape dimensioned to receive the ribbon.

6. The printing mechanism for a hand held printer of claim 5, wherein the shape of the drive roller means is concave.

7. The printing mechanism for a hand held printer of claim 4, wherein a portion of the thermal transfer ribbon passes about the support member, the support member being formed in a shape dimensioned to receive the thermal ribbon.

8. The printing mechanism for a hand held printer of claim 4, wherein the shape of the support member is concave.

9. The printing mechanism for a hand held printer of claim 1, wherein the head biasing means is a spring which presses against the thermal head.

10. The printing mechanism for a hand held printer of claim 1, wherein the roller biasing means comprises a spring for pressing the roller.

11. The printing mechanism for a hand held printer of claim 1, wherein the drive roller means comprises a drive roller.

12. The printing mechanism for a hand held printer of claim 4, wherein the support member comprises a support roller.

13. The printing mechanism for a hand held printer of claim 4, wherein the support member is a shaft.

Images